In the manufacture of semiconductor chips and microelectronic devices, a silicon wafer or other substrate is exposed to a variety of different processes in different processing chambers. The chambers expose the wafer to a number of different chemical and physical processes whereby minute integrated circuits are created on the substrate. Layers of materials which make up the integrated circuit are created by processes including chemical vapor deposition, physical vapor deposition, epitaxial growth, and the like. Some of the layers of material are patterned using photoresist masks and wet or dry etching techniques. The substrates may be silicon, gallium arsenide, indium phosphide, glass, or other appropriate materials.
In these manufacturing processes, plasma may be used for depositing or etching various material layers. Plasma processing offers many advantages over thermal processing. For example, plasma enhanced chemical vapor deposition (PECVD) allows deposition processes to be performed at lower temperatures and at higher deposition rates than in analogous thermal processes. PECVD therefore allows material to be deposited at lower temperatures.
The processing chambers used in these processes have many components to control temperature, gas concentrations and pressures, high frequency radio waves, applied electrical charges, relative difference between different parts and many other parameters of the process. At the same time because the features formed on the workpiece are very small, the processing parameters must be controlled very precisely. In addition, the workpieces must be able to be placed in and out of a chamber quickly to minimize fabrication delays.
Any fault or mismatch in the hardware, configuration, or parts in the chamber setup can render the processes in the chamber difficult to precisely control or may simply change the parameters of a process. This affects how the device on the wafer is fabricated and may reduce yields or cause bad batches. In some cases, there may be a tool down situation with the chamber. These events can potentially result in unscheduled downtime, yield loss or wafer scrap.
Chambers are normally inspected and tested by opening the chamber and manually inspecting each of the components. The same is true for troubleshooting hardware installation issues, such as misplaced parts, missed RF (Radio Frequency) gaskets, etc. This kind of inspection and test is slow and requires that the chamber be taken out of production, flushed and allowed to cool followed by a long recovery process.